Can I redirect port 25 with a dynamic dns service?

[blu at vl.com (Tom Metro)]

Rich Braun wrote:
> Bill Horne wrote:
>> ...I'd like to get port 25 going again too and I'd like alternatives to 
>> dyndns.org's Mail Hop service.
> 
> Well, in theory a hosting service or ISP could assign a static IP out of one
> of its blocks and set up a redirect which would relay packets the same way a
> NAT router does.

Another approach would be to use an SMTP proxy server - software that is 
  far more plentiful these days due to their use in spam filtering 
setups.  (In my own mail setup I use a proxy that, as a side effect, 
moves the SMTP traffic from port 25 to 125.) Such a server would of 
course need to run at an ISP or hosting company, and your public MX 
records would point to it.

But the simple approach is to stick with the approach DynDNS uses for 
their MailHop Relay service. Why is it that you are unsatisfied with DynDNS?


Bill Horne wrote:
> Which dynamic DNS services will map port 25 to something else?

Here are the lists I turn to when looking for dynamic DNS providers:

http://www.oth.net/dyndns.html
http://dns.highsynth.com/

I'm sure you can also find some small ISPs that will do this. It doesn't 
really require anything special, as many MTAs allow you to specify a 
destination port in their routing rules.

  -Tom